Sizes, and which limit binds
Updated
On this page8
The range
Fifteen to 120 mL across 203 containers, with 127 at or under 100 mL. That is a travel range rather than a general small-bottle range, and the distribution reflects the constraint it was built for.
The small end
Fifteen to 30 mL suits a perfume decant, a serum or a sample. It is also the size where a flat or oval shape earns its keep, because a round bottle of that volume rolls around a bag.
The middle
Fifty to 100 mL is the core of a carry-on set: shampoo, conditioner, lotion, sunscreen. Comfortably under the stricter limit, and enough for a week without being bulky.
The top of the range
Up to 120 mL, which is above the usual carry-on screening figure and well under the hazmat ceiling. Those are checked-baggage or home-refill sizes and should be described that way rather than as cabin sizes.
Capacity is what both rules measure
Not the fill. So a 120 mL bottle holding 80 mL is a 120 mL container for both the hazmat ceiling and for screening, and selling it as a cabin-compliant bottle on the basis of its contents would be wrong.
Which makes the set the product
Travel bottles sell in sets, so the set is where the sizes get decided. A set entirely under the screening figure is simpler to describe and harder to get wrong than a mixed one.
And the aggregate limit reaches the set
The hazmat exception caps each person at 2 liters in aggregate. A large set of 120 mL bottles starts to interact with that, which is an unusual constraint and worth knowing before designing a sixteen-piece kit.